Bag top opening device



Aug. 1, 1967 H. K. FOX

BAG TOP OPENING DEVICE 2 Sheets-Sheet 1 Filed Feb. 12, 1965 INVENTOR.

#0204. A. Fox

lrfomvz s Aug. 1, 1967 H. K. FOX

BAG TOP OPENING DEVICE 2 Sheets-Sheet 2 Filed Feb. 12, 1965 FIG. 5

INVENTOR. 15092040 1% F'ox United States Patent 3,333,496 BAG TOP OPENING DEVICE Harold K. Fox, Minneapolis, Minn., assignor to Bemis Company, Inc., a corporation of Missouri Filed Feb. 12, 1965, Ser. No. 432,106 Claims. (Cl. 83-468) This invention relates to a new and novel device utilizable to facilitate the opening of tube stock material such as a bag. More particularly this invention relates to new and novel apparatus for spreading peripherial edge portions of a bag top between the leading edge and trailing edge of a bag top including slitting said leading edge and trailing edge and laying open said peripheral edge portions between the slits for any desired purpose.

In the manufacture of bags and in filling bags, frequently difficulty is encountered in providing an initial opening into the open end of a bag. For example, in a filled plastic bag prior to the time a heat seal top closure is formed, the upper portions of the sidewalls of the bag are in an abutting position and will tend to stick together; but should be separated for purposes of cleaning. Also, when plastic bags in a flat folded condition are removed h'om a magazine and it is desired to open the bag for filling, frequently the opening of the upper top edge portions of the bag is diflicult and uncertain due to blocking in the plastic bags. In order to overcome problems of the aforementioned nature and to provide for spreading juxtaposed edge portions including slitting joined edges of any material such as plastic, paper, textiles where two or more thicknesses or plies are to be slitted and spread for any purposes, this invention has been made.

One of the objects of this invention is to provide new and novel apparatus for spreading juxtaposed peripheral edge portions including slitting joined edges and laying open said portions of two abutting plies of material having said edge portions and edges for any purpose whatsoever. Another object of this invention is to provide new and novel apparatus for slitting the leading edge and trailing edge of the uppermost portion of a bag in an upright condition wherein the side walls are in juxtaposed condition, and then to lay open the upper side wall portions. A further object of this invention is to slit, separate and lay open edge portions of the side walls of a bag, or two or more plies or thicknesses of a material that are in face to face abutting relationship.

Other and further objects are those inherent in the invention herein illustrated, described and claimed and will become more apparent as the description proceeds.

An additional object of this invention is to provide new and novel apparatus mountable in a vertical, horizontal, inverted or any angular position desired, together with feeding the material in a corresponding manner to achieve any of the previously mentioned objects.

To the accomplishment of the foregoing and related ends, this invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

For purposes of facilitating the disclosure of this invention, the drawings show and the specification describes the apparatus of this invention for spreading open juxtaposed peripheral edge portions of the material that is being conveyed with the juxtaposed portions extending generally vertically. However, it is to be understood the apparatus can be mounted for spreading, including slitting, juxtaposed peripheral edge portions where the said portions extend in any desired direction including vertically, horizontally, inverted, or any other angular direction desired.

The invention is illustrated by reference to the drawings wherein the same reference numerals refer to the same parts and in which:

FIGURE 1 is a plan view of the bag top opening device of this invention together with a fragmentary plan view of associated apparatus for a bag top sealing machine, said apparatus being diagrammatically shown in FIG- URE 9;

FIGURE 2 is a side view, part in cross section and part of the belt guides broken away, of the structure of FIGURE 1;

FIGURE 3 is an enlarged longitudinal vertical elevational view, part in cross section, of the device of this invention, said view being generally taken along the line and in the direction of the arrows 3-3 of FIGURE 1 to illustrate the structure of said device and associated structure on which it is mounted;

FIGURE 4 is a transverse cross sectional view of the device of this invention, said view being generally taken along the line and in the direction of the arrows 4-4 of FIGURE 1 FIGURE 5 is a front end view of the device of this invention, said view being generally taken along the line and in the direction of the arrows 5--5 of FIGURE 3;

FIGURE 6 is a fragmentary plan view illustrating the leading edge of a bag top just prior to it being engaged by the slitter knife, the thickness of the bag and the spacing of the pulley sheaves being exaggerated;

FIGURE 7 is a fragmentary transverse cross sectional view showing the bag top after it has been slitted and the bag top side wall portions being held in a laid open position by the guide shoe;

FIGURE 8 is a vertical view of the knife blade and clamp in their relative mounted positions such as shown along the line and in the direction of the arrows 88 of FIGURE 4; and

FIGURE 9 is generally a diagrammatic plan view showing the relative position of the structure of FIGURES 16 to the remaining structure of a bag top sealing machine.

In order to facilitate the understanding of the use of the invention, the invention will be described with reference to being mounted on a bag top heat sealing machine such as described in co-pending US. Patent appli cation Serial No. 258,446, filed February 14, 1963, and entitled, Bag Top Sealing Machine and Method for Forming a Bag Top Closure, Patent No. 3,284,433, issued November 22, 1966 and which is assigned to the same assignee as this application. The bag top slitting and opening device of this invention may be mounted on the machine of Serial No. 258,466 just rearwardly of the bag top guides 88, 89 shown in FIGURE 1B, the bag top cleaning assembly 18 of said application being eliminated and with the plate 31 just forwardly of the nozzles 19.

The bag top opening and slitting device, generally designated 10, of this invention is, for example, mounted on such a heat sealing machine as in part diagrammatically represented in FIGURE 9. The heat sealing machine of FIGURE 9 includes a pair of pulley sheaves 12 at one end that are driven in synchronism in opposite directions by a motor 13 and a pair of idler pulley sheaves 14. The sheaves 12, 14 are mounted respectively at the rear and forward end portions of longitudinally elongated support members 25, 26. An endless belt 15 is extended around one of the pulley sheaves 12, an intermediate idler pulley sheave 16 next around one of the idler pulley sheaves 14 and thence back to the driven pulley sheave 12, said pulley sheaves 14, 16 being mounted on support member 25. A second belt -17 is likewise extended around the other driven pulley 12, idler pulley sheave 14 and the intermediate idler pulley sheave 16, the last mentioned pulley sheaves being mounted on support member 26. Pulley sheaves 14 and 12 hold theinner runs 15a and 17a of belts 15 and 17 respectively in abutting relationship. Guides described hereinafter and additional guides (not shown) as provided intermediate pulley sheaves 12 and 14, such as indicated in the aforementioned co-pending application.

Longitudinally adjacent the pulley sheaves 14 there is provided a bag top trimming assembly 20, while adjacent the pulley sheaves .12 there is provided a pair of hot air nozzles 21 which are mounted to direct jets of hot air against the top edge portions of a bag top as it is passed therebetween. Just rearwardly of the sheaves 14 and overhanging the inner runs of the belts 15, 17 is the bag top slitting and opening device 19 of this invention, while intermediate rearwardly of the device there is a bag top hold open guide shoe and cleaning assembly, generally designated 22. The assembly 22 is located forwardly of the hot air nozzles 21.

Intermediate the bag top trimming assembly and the bag top slitting and opening device of this invention, there is provided a pulley sheave 23 bearing against inner run a and a pulley sheave 24 bearing against the inner run 17a, pulley sheaves 23, 24- being transversely opposite one another for holding the adjacent portions of the inner runs in abutting relationship as they pass between said sheaves. The sheaves 23, 24 are journaled for rotation on the support members 25, 26 respectively, the support members being transversely spaced. Belt guides 18a, 18b are mounted on members 25, 26 to resiliently hold the inner runs in abutting relationship, said guides being longitudinally between the trimming assembly and pulley sheaves 23, 24. That is guide 18a is mounted in the manner guide 19 is mounted as will be described hereinafter. Guides 18a, 18b are mounted relative the trimmer assembly in the location illustrated for guides 88, 89 of said co-pending application.

Just rearwardly of the sheaves 23, 24 and mounted on the support plate 26 to extend upwardly thereabove is a longitudinally elongated support bracket 28. Bracket 28 mounts the bag top opening device 10 which includes a stud bolt 30 extended through a vertically elongated slot 29 in the plate 28. The bolt 30 is threaded at opposite ends, has an annular flange 30a adjacent one threaded end and an elongated nonthreaded portion intermediate said flange and the opposite threaded end. A nut 31 is provided for adjustably positioning and holding the bolt 30 in an adjusted position relative the axial height of the slot 29, the nut abutting against one side of bracket 28 and flange 3012 against the opposite side.

A wing nut 34 threaded on the opposite end of the bolt for abutting against one end of the apertured block mandrel 35 holds the mandrel in abutting engagement with the flange 30a of the bolt 30. The mandrel 35 is mounted on the central unthreaded portion of the bolt 30 for pivotal movement about a horizontal axis. The mandrel has opposite, exterior threaded ends 35a, 35c and an intermediate portion 35b that is rectangular in longitudinal vertical cross section. An adjustment nut 38 is threaded on portion 35a of the mandrel to abut against one face of the clamp plate 36 and blade mounting block 41 While a second adjustment nut 39 is threadedly mounted on the threaded portion 35c of the mandrel to have one face abut against the opposite face of the clamp plate and the blade mounting block. Thus members 38 and 39 hold the block 41 against transverse movement relative the mandrel 35. At the same time, the transverse spacing of the block 41 may be varied relative the plate 28 by the appropriate threading of nuts 38, 39 on the mandrel.

As inferred above, the mandrel mounts a blade mounting member that includes the blade mounting block 41 which has a rectangular cut out 42 that is open at the top and extends approximately half the height of the block 41, the elongated clamp plate 36 being of a greater longitudinal length than block 41 and cap bolts 44 being extended through appropriate apertures in the plate 36 and threaded into the upwardly extending legs 41a, 41b of the block that define the side walls of the cut out 42. The plate 36 is thus attached to the blade mounting block to form a cover plate for the 'cut out, said cover plate having a rear portion extending a substantial distance rearwardly of leg 41b. The vertical dimension between the lower surface of plate 36 and the bottom horizontal surface of the cut out is such that the plate 36 and the bottom wall of the cut out form a close fit with the respective horizontal surfaces of the rectangular portion of the mandrel when the mandrel is located in the cut out such as illustrated in FIGURES 3 and 4. Further, the transverse width of members 36, 41 is greater than that of rectangular portion 35b such that the nuts 38, 39 will bear against opposite faces of said members 36, 41 and permit transverse adjustment.

In order to permit limited longitudinal adjustment of the position of the blade mounting member, the longitudinal length of the cut out is substantially greater than the corresponding longitudinal dimension of the rectangular portion 35b,'for example, such as illustrated in FIG- URE 3. A longitudinally extending stud bolt 46 is threaded in an aperture formed in the upwardly extending leg 41b to bear against one vertical surface of the rectangular portion 35b while a second stud bolt 47 is threaded through the other leg 41a to bear against the opposite vertical surface of portion 35b. As may be noted, bolts 46, 47 are oppositely disposed and thus by unthreading one and threading the other a corresponding amount, the blade mounting member will be longitudinally translated relative the rectangular portion 35b and firmly held in the adjusted translated position.

Formed in the blade mounting block is a longitudinally elongated slot 49 that opens through the bottom surface of said block and extends the longitudinal length of block 41. The slot at the forward end-of block 41 extends to a greater elevation that the rearward end to form a curved shoulder 490 such as shown in FIGURE 3. As may be noted from FIGURE 4, one vertical wall forming the slot is located substantially centrally between opposite outer vertical surfaces of block 41 while the other vertical wall is located more closely adjacent the wing nut. The slot is provided for mounting a generally flat knife blade 50 with one surface in abutting engagement with the slots centrally located Wall, there being provided a knife clamp 51 in the slot which is retained in abutting engagement with the opposite surface of the knife by knurl headed bolts 52 that are threaded in appropriate apertures in the blade mounting member to bearagainst the surfaces of the apertures 51c, 51d drilled partially through the clamp on the side opposite the knife. A roll pin 53 is extended through slot 49 to bear against the rear vertical edge of blade 50 to facilitate correctly posi-' tioning the blade relative the slot 49.

Referring to FIGURE 3, it is to be noted that the knife in a mounted position has a forward lower edge portion 50a that extends to an elevation vertically beneath the bottom surface of the blade mounting block, has a straight bottom edge and also extends a substantial distance forwardly of said block. The bottom edge 50a intersects the blade cutting edge 5% at point P, the cutting edge being inclined upwardly and rearwardly from point P at about a 45 angle and being located in a vertical plane. Also, the blade mounting block has a forwardly projecting part having a vertical surface 41d that is inclined rearwardly and outwardly from one vertical side face of the knife and a second vertical face 41e that is inclined rearwardly and outwardly from the opposite face of the knife blade. The clamp 51 has a vertical surface 51a that in the knife blade mounted position forms a continuation of a surface 41e. The forward projecting part also has a first oblique surface 41 that along one edge intersects the surface 41d and in a longitudinally rearwardly direction from surface 41d is inclined downwardly and rearwardly and is also inclined upwardly in a direction transversely outwardly from the blade 50. A second oblique surface 41g is provided on the side of the blade opposite surface 41 to be inclined downwardly and longitudinally rearwardly from surface 41e and upwardly in a transversely outwardly direction from the clamp 51. The purpose of providing a surface portions 41d, 41e, 41g and 51a inclined in the manner described above will become more apparent hereinafter.

A11 adjustment screw 66 is threaded into mount 67 so that the lower end of the screw bears against the upper surface of the rearward end of the cover plate 36. The mount 67 has a transversely extending threaded portion extended through an aperture in bracket 28. Nuts are threaded on the threaded portion to bear against opposite faces of the bracket. Also, there is provided a set screw 69 that is threaded into the mount 67 for clampingly retaining screw 66 in a vertically adjusted position. With the aforementioned structure, when the cover plate bears against screw 66 in its proper adjusted position the bottom edge 50a of the knife extends horizontally and the knife in an assembled mounted condition cannot be further pivoted in the direction of the arrow 70 from that illustrated in FIGURE 2. However, upon loosening the wing nut 34, the blade mounting block and mandrel may be pivoted on bolt in the direction opposite arrow 70 whereby the bottom edge of the knife extends upwardly and forwardly from the position illustrated in FIGURE 2. By pivoting the mandrel and the blade mounting block in the aforementioned manner, the bolts 52 may be loosened and the blade easily removed to be, for example, sharpened. The blade may be readily replaced by placing the clamp 51 and the knife blade 50 in the slot and tightening the bolts 52; and thence the mandrel and blade mounting block pivoted in the direction of the arrow 70 until the cover plate abuts against the adjustment screw 66.

To be mentioned is that the majority of the weight of the structure mounted by stud bolt 30 is located longitudinally adjacent sheaves 23, 24 and vertically beneath the transverse axis of said stud bolt. Further the knife plate point P is located more forwardly than any other structure of the device 10, the knife blade being mounted to have its cutting edge extend horizontally outwardly of the knife blade mounting structure in a direction opposite the movement of the material to be slitted. As a result the knife will not of its own accord pivot such that point P moves upwardly when point P engages material being carried by inner runs 15a, 17a.

A guide shoe 54 has a right angle portion that is bolted at 55 to the bracket 28 to have the longitudinally elongated portion of the guide shoe overhang the belt inner runs and adjacent portions of guides 19, 43 from a position adjacent the blade mounting block to a position substantially horizontally rearwardly thereof. As may be noted from FIGURE 2 the guide elongated portion has an upwardly curved part 54a located directly beneath the rearward portion of the block 41 and a generally horizontally longitudinally rearwardly extending part 54b. The bottom surface of part 5412 is located more closely adjacent the belt runs 15a, 17b than the bottom surface of the block 41.

The guide shoe 54 serves to hold the bag top side edge portions in a spread apart, generally horizontal, laid open position (see FIGURE 7) as the bag top is moved longitudinally rearwardly from the bag top opening device to the cleaning assembly, said assembly including a motor 58 that is bolted to one side of the support plate. The motor has a transversely extending motor shaft 59 extended through the support plate to mount a narrow width brush 60 to rotate about a transverse horizontal axis. As may be noted from FIGURES 1 and 2, the brush is positioned to have one circumferential portion extend to approximately the same elevation as the lower surface 54b of the guide at a location just rearwardly of the guide. Further, as may be noted from these figures, the brush is positioned to be directly vertically above adjacent surface portions of the runs 15a, 17a. The motor dn'vingly rotates the brush 60 in the direction of the arrow 61 to brushingly engage the bag top side wall interior surface portions in a manner described hereinafter. Although this application describes the brush being rotated by a motor, it is to be understood that said brush may be drivingly rotated by the air such as described in the aforementioned co-pending application.

The previously mentioned guide 43 is mounted on the support member 26 to extend longitudinally from just rearwardly of the pulley sheave 24 to rearwardly of the brush 60, guide 43 serving to hold the inner vertical surface of run 17a very closely adjacent or in abutting engagement with the adjacent surface of run 15a. Guide 19 extends longitudinally such as described for guide 43 other than it extends from adjacent sheave 23 and bears against inner run 15a to resiliently retain it in abutting engagement with inner run 17a. In order to resiliently mount the guide 19 there is provided a transversely extending stud bolt 65 that at one end is welded to the vertical surface of guide 19, that is opposite inner run 15a and at the opposite end slidably extends through apertured block-62. A nut 63 is threaded onto the opposite end of stud bolt 65, there being provided a coil spring 64 on the stud bolt that at one end bears against the block 62 and at the opposite end bear against the guide 19 such that the guide 19 is resiliently urged toward inner run 17a. As may be noted from FIGURE 1 and FIG- URE 7, adjacent vertical surfaces of guides 19, 43 are transversely spaced and extend directly beneath the brush 60 and the blade mounting block. Sheaves 23, 24 and guides 19, 43 serve to hold the inner runs closely adjacent one another as said inner runs move material to be slitted and separated by device 10 and cleaned by brush 60. 1

The structure of the invention having been described, the use thereof will now be set forth. Assuming that the bag top opening and slitting device is to be utilized on a heat sealing machine, members 35, 36, 38, 39, 50 and 51 are assembled on the stud bolt 30 in the manner described heretofore. The stud bolt 30 has its threaded end extended through the slot 29 and the nut 31 threaded thereon after the stud bolt is moved to an elevation that the knife blade bottom edge 60a (in a horizontal condition) is at an elevation of a few thousandths of an inch above the uppermost surface portion of the outer periphery portion of the pulley sheaves 23, 24. The adjustment nuts 33, 39 are threaded on the mandrel such that the blade mounting block is translated in a transverse direction to position the knife blade directly above and centrally located relative the nip between sheaves 23, 24. Also adjustment bolts 46, 47 are threaded such that the blade mounting block is longitudinally translated to move the knife blade very closely adjacent the nip of sheaves 23, 24 without touching said sheaves. That is, the knife blade mounting structure is adjusted to position the point P of the knife blade horizontally very closely adjacent the sheaves 23, 24 and slightly vertically above said sheaves; and to nearly as possible have the point P located in a longitudinally extending vertical plane between adjacent surfaces of inner runs 15a, 17a. To be mentioned is that with the knife blade located as described above,

the rearward top surface of the cover plate 36 abuts against the lower end of the adjustment screw 66 which is threaded into the mount 67.

With the motor 13 running, belts 15, 17 are driven such that the inner runs move in the direction of the arrows 71 at the same speed. Now a non-gusseted bag 72 which has previously been filled with product, has the upper side Wall edge portions positioned in abutting relationship and the leading vertical edge 72b moved into the entry nip between inner ends 15a, 171; such that the inner runs retain the bag top side wall portions in abutting relationship in a manner described in the aforementioned co-pending application. At this time the bag side wall portions extend a substantial distance above the inner runs a, 17a to have a portion thereof trimmed off by the trimmer assembly 20 to form bag top edges 72a that are at the same elevation above the support members 25, 26 for successive bags. The bag is moved in the direction of the arrows 71 such that the leading edge 72b (juncture'of sidewalls 72c, 72d) first passes through the exit nip of pulley sheaves 23, 24 to be engaged by the point P of the knife blade at a location vertically beneath the top trimmed edges 72a. As may be noted from FIGURES 2 and 6, the point P is transversely located to slit the leading edge 72b at a location at the point P and edge 50b enters between the top portions of side wall 72c, 72d of the bag. As the bag is further advanced along with the inner runs in the direction of the arrow 71, the leading edge portion constantly engages a portion of knife edge Sill) at a higher elevation so that the leading edge is slit upwardly from the location that point P first engages the bag. The trailing edge is subsequently brought into engagement with the knife blade and likewise slit.

As the leading edges of the bag which now have been slit from elevation of point P to the top horizontal edges 72a, the slitted leading edges are advanced by the belts to engage surface 51a of one side of the knife blade and surface 41d on the opposite side of the knife blade. Since the surfaces diverge from one another in a rearward direction, the portions of side walls 72d, 720 above the belt inner runs are spread apart. Also, the leading edge portion of the bag top are brought into engagement with the oblique surfaces 41g, 41f respectively which are inclined to fold the slit side wall top portions toward a somewhat horizontally extending laid open condition overlaying the belt guides 43, 19 with their inner surfaces facing up such as illustrated in FIGURE 7. Point P subsequently slits the trailing edge 72e in a manner similar to the slitting of the leading edge.

As the side wall slitted top portions are moved rearwardly of oblique surfaces 41g, 41 they are held in a laid open condition by the flat bottom surface of the blade mounting block and subsequently are moved into engagement with the guide shoe 54 which holds said portions in said laid open condition as the bag is moved rearwardly to pass beneath the brush 60. The brush 60 brushes against the slit interior side wall bag top portions that are above belts 15, 17 to clean the inner bag surfaces in the manner described in the aforementioned co-pending application. Thus if the side wall portions 72d, 720

that extend vertically above the inner runs 15a, 17a are joined at the leading edge 72b, the knife will slit the leading edge, and thence the trailing edge while separating the portions extending above the belts and lay them open to be, for example, cleaned by a brush 60; or for any other desired purpose. It is to be understood that ,with the knife 50 mounted by structure described heretofore the knife may be used not only :for slitting the leading edge and trailing edge of a bag top but also to separate the side wall portions of two plies or thicknesses of abutting material extending above the conveyor belts.

As indicated above, the knife point P is located to engage the leading edge of two or more thicknesses of material, for example, a bag top, at an elevation vertically beneath the top edges 72a; and also at a location just after the leading edge passes through the nip of the pulley sheaves 23, 24 whereby layers 72d, 72c are being firmly held in abutting condition by inner runs 15a, 17a. Accordingly, point P punctures a bag at the intersection therewith and thence cuts in an upper direction as the bag is moved rearwardly rather than acting to fold the leading edge and trailing edge portions of the bag downwardly. Additionally, through the provision of the adjustments described heretofore, the knife blade including its point P is positionable to slit the leading edge of the bag or other joined plies of material and then pass between said plies to separate said plies rather than deflecting the leading edge portions to one side or the other of the knife blade. Thus there is provided structure that may be utilized to readily open the top edge portions of the bag top to facilitate cleaning the inner surfaces thereof; or for purposes to facilitate gaining entrance to the bag in the event the bag top opening device is used on a bag filling machine where blocking of non-gusseted fiat fold plastic bags makes opening difiicult by for example, vacuum cups, or for spreading top edge portions of two plies of material that tend to block or adhere together and which may or may not be joined together at vertical leading and trailing edge portions.

As illustrated in FIG. 7, the portions 171, 17g of the lengths of material 72d, 720 respectively are held in abutting relationship and extend vertically. However, the apparatus of this invention will function as described for spreading lateral edges 72a, 72a (which in a bag intersect the trailing and leading edges and extend at right angles thereto) with the portions 17 17g and periph-' eral lateral edge portions extending at any desired angle since the lateral edges 72a, 72a are spaced only a small distance outwardly of runs 17a, 15a (for example a A") and the cutting edge of the knife extends adjacent the exit nip of sheaves 23, 24 that back the portion of the runs adjacent where the joined leading edges are slitted and the lateral edge portions initially spread apart.

As many widely apparently different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments herein.

What I claim is:

1. In apparatus for separating juxtaposed lateral edge portions of two lengths of flexible material'having leading edges and peripheral lateral edges, a frame, means on said frame for conveying said lengths in a longitudinal direction and supportingly holding said lengths in face to face abutting relationship at a location spaced from and adjacent said lateral edge portions, the improvement comprising a knife blade having a knife point and an elongated cutting edge terminating at said pointand means on the frame for mounting said knife blade. adjacent saidconveying means in the path of travel of said edge portions as said material is being conveyed, and at a position that the knife blade initially engages said leading edges at a location spaced from said lateral edges.

2. The apparatus of claim 1 further characterized in' that the blade has an elongated bottom edge terminating at said point and side surfaces, and that the last mentioned means includes a blade mounting member having the blade attached thereto, said blade mounting member having vertical surface portions that intersect opposite side surfaces along the cutting edge and are inclined to diverge from one another in said direction to facilitate the spreading of said edge portions.

3. The apparatus of claim 2 further characterizedin.

tend transversely to said direction and in overhanging re- V lationship to the path of travel of said material as the' material is being conveyed by the conveying means, and means for mounting said knife blade on the stud bolt in the aforementioned manner 5. The apparatus of claim 4 further characterized in that said blade mounting member includes a mandrel mounted on said stud bolt, said mandrel having a portion generally rectangular in longitudinal vertical cross section, and a knife blade mounting block having a cut out that is rectangular in vertical longitudinal cross section to receive the mandrel rectangular portion, the longitudinal horizontal dimension of the cut out being substantially greater than the corresponding dimension of said mandrel rectangular portion, and adjacent means mounted by said blade mounting block and engageable with the mandrel for securing said blade mounting block in various selected translated longitudinal positions relative the mandrel.

6. The apparatus of claim further characterized in that the blade mounting block has a longitudinally elongated slot opening adjacent the conveying means to have the knife blade extend therein and that the blade mounting means includes a clamp plate mountable in said slot in abutting engagement with the knife blade and means on the blade mounting block for releasably clamping said blade and clamping plate within the slot,

7. In a machine for forming a heat seal seam in a nongusseted bag having upper sidewall portions with joined leading edges and trailing edges and top edges, said machine including a flame, a pair of endless conveyor belts having inner runs, means for mounting said belts on the frame with said inner runs sufficiently close to supportingly hold at least the adjacent areas of said sidewall portions in abutting relationship and the top edges horizontally thereabove, and driving said belts at the same speed with the inner runs moving in one direction to convey said bag, means on the frame adjacent said inner runs for forming a heat seal scam in said sidewall portions at an elevation above said inner runs as the bag is being conveyed, and means mounted on the frame adjacent the inner runs for slitting said joined edges and separate the side wall portions above said inner runs, the last mentioned means including a knife blade having a cutting edge terminating at a point and means for mounting said knife blade on the frame in a position that the knife blade initially engages said leading edge at said point to upwardly slit said leading edge as the bag is being conveyed and thence move the sidewall portions above the inner runs apart.

8. The structure of claim 7 further characterized in that the belt mounting means includes a belt sheave mounted on the frame adjacent each inner run for holding the adjacent inner run portions in substantial abutting relationship, said sheaves being mounted closely adjacent each other to form an exit nip, and that the knife blade mounting means includes means for mounting the knife blade at a slightly higher elevation than said sheaves and with the blade extending adjacent to and vertically above the sheave exit nip.

9. The structure of claim 8 further characterized in that the knife blade mounted in the aforementioned manner has a bottom edge portion extending generally parallel to the direction of movement of the inner runs and terminates at a knife point, and that said cutting edge terminates .at said point and is inclined upwardly from point in said one direction.

10. Apparatus for separating the lateral edge portions of two lengths of flexible material having leading edges and peripheral lateral edges comprising a frame, means on said frame for conveyingsaid lengths in a longitudinal direction and supportingly holding longitudinally extending portions of said lengths in face to face abutting relationship at a location spaced from and adjacent said lateral edge portions, the aforementioned means including a pair of endless conveyor belts each having an inner run to abut against one of said lengths, and means on said frame for retaining said inner runs closely adjacent one another as said lengths are being conveyed, a knife blade having a cutting edge, and means for mounting said knife blade on the frame adjacent said runs and in position to pass between said lateral edge portions as they are being conveyed to spread said lateral edge portions, the last mentioned means mounting the knife blade to have the cutting edge extend outwardly from said inner runs in said longitudinal direction.

11. The apparatus of claim 10 further characterized in that said knife blade has a point, said cutting edge terminating at said point, and that the knife blade mounting means includes means for mounting said knife blade with the knife blade point in position to engage said lengths prior to the remaining portion of the blade engages said lengths.

12. The structure of claim 10 further characterized in that the knife blade mounting means includes means for spreading said lateral edge portions to extend outwardly away from one another and that there is provided means on the frame for cleaning the inner surfaces of the lateral edge portions after said lateral edge portions have been spread by the spreading means.

13. The structure of claim 12 further characterized in that the cleaning means includes a brush and means for drivingly rotating said brush adjacent said inner runs to engage said inner surfaces as said lengths are conveyed by said conveying means,

14. The structure of claim 13 further characterized in that the knife blade mounting means includes a knife blade mounting block having surface portions extending horizontally outwardly of the blade on either side thereof, and that said spreading means comprise surface portions of said block on either side of the blade that incline divergingly outwardly from one another and away from the knife blade in said longitudinal direction.

15. The structure of claim 13 further characterized in that the said two lengths are side walls of a non-gusseted bag joined at said leading edges and that said knife blade mounting means mounts said knife blade to slit said joined leading edges outwardly of said inner runs as the said lengths are being conveyed.

References Cited UNITED STATES PATENTS 2,853,842 9/1958 Vredenburg 53-384 3,068,730 12/1962 'Johnson 83l84 BERNARD STICKNEY, Primary Examiner. 

1. IN APPARATUS FOR SEPARATING JUXTAPOSED LATERAL EDGE PORTIONS OF TWO LENGTH OF FLEXIBLE MATERIAL HAVING LEADING EDGES AND PERIPHERAL LATERAL EDGES, A FRAME, MEANS ON SAID FRAME FOR CONVEYING SAID LENGTHS IN A LONGITUDINAL DIRECTION AND SUPPORTINGLY HOLDING SAID LENGTHS IN FACE TO FACE ABUTTING RELATIONSHIP AT A LOCATION SPACED FROM AND ADJACENT SAID LATERAL EDGE PORTIONS, THE IMPROVEMENT COMPRISING A KNIFE BLADE HAVING A KNIFE POINT AND AN ELONGATED CUTTING EDGE TERMINATING AT SAID POINT AND MEANS ON THE FRAME FOR MOUNTING SAID KNIFE BLADE ADJACENT SAID CONVEYING MEANS IN THE PATH OF TRAVEL OF SAID EDGE PORTIONS AS SAID MATERIAL IS BEING CONVEYED, AND AT A POSITION THAT THE KNIFE BLADE INITIALLY ENGAGES SAID LEADING EDGE AT A LOCATION SPACED FROM SAID LATERAL EDGES. 